BIOL 1000 Study Guide - Midterm Guide: Archaea, Phosphodiester Bond, Hydrolysis
2 Apr 2017
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Chapter 4, 5, 6, 7, 12 and 15. 1, 9. 2 midterm content. Oct 28th biol 1000 lecture dna replication. Therefore, as soon as strands separate (unwind), replication occurs. Origin of replication typically happens where you have a lot of a & t bases. Multiple origins of replication occurring at once so rate of replication is fast. Enzyme helicase: splits two strands of dna at replication fork. Unwinding needs energy in form of atp. Secondary dna structure: where a strand folds back onto itself in an effort to maintain double-strand structure: single-stranded binding proteins, bind to single strand of dna so this doesn"t happen, they stabilize separate strands. As helicase is unravelling, due to untwisting, dna can over twist and therefore hit s a block so that helicase cannot proceed anymore. Topoisomerase relieves over-twisting, makes small cut in dna backbone and in doing that it relaxes that over-twisting, therefore allowing helicase to proceed without any hindrance.
